"It's like a fishtail on steroids," said Pearson, who investigated the accident.

Crose, of Winnebago, has pleaded not guilty to all charges. His trial continues this week before Judge Brian Shore.

His Mustang remained in a flat spin as it flew across the median and into the path of oncoming traffic.

Crose's wife, Dea, 33, stepson Cole, 15, and daughter Alexis, 13, were ejected from the Mustang as it struck a 2002 Dodge Caravan. Their broken bodies were left strewn across the median and highway. The Mustang split open when it hit the van in a manner "similar to peeling open a sardine can," Pearson said.

Dea was declared dead at the scene. Cole died at the hospital. Alexis and Crose were critically injured.

Inside the Dodge, the impact crushed Mark Mathias' legs, broke his hip, broke a bone in his ankle and left him in a coma for nine days. Mathias's teenage son, riding in the backseat, suffered a lacerated kidney and ruptured spleen. His wife and daughter also were in the vehicle but suffered less severe injuries.

Assistant State's Attorney Renee Dehn-Miller is arguing that Crose was driving recklessly and weaving through traffic, and that his actions caused the deaths of his family members and badly injured occupants of the other vehicle.

But Crose's attorney, Debra Schafer, will challenge crime scene analysis that claims Crose was driving at speeds in excess of 120 mph.

Schafer said Crose is not guilty of reckless homicide or reckless driving. Instead, she said, the crash was an accident that occurred when he tried to get away from another car that was being driven erratically and sending out plumes of black smoke.